This invention relates to solar energy heating systems.
Significant technological progress has been made in solar heating systems in recent years, following the realization of limits on fossil fuels and the rapidly increasing cost thereof. Solar heating is becoming a practical reality in some geographical areas, particularly in the southern and southwestern parts of the United States, sometimes designated the "Sun Belt". In the more northern regions, as in the northwestern, midwestern, and northeastern parts of the United States, where the number of sunny days is less, there is difficulty justifying the installation cost of solar equipment because of the considerably lower efficiency thereof. There are many cloudy or partly cloudy days when the collector cannot generate sufficient heat to meet requirements, particularly during cool mornings and evenings. Hence, any solar system of the presently known type is typically inactivated at such times, with the heat then being generated by fossil fuel combustion. Unfortunately, these same regions of cooler climate are more in need of whatever solar energy there is available, even if insufficient to meet the total heat requirements.